Did they say in the letter what kind of proofs you need to submit? In my case, I submitted literally everything they outlined in the letter: lease showing both names, government mail received for both sponsor and applicant showing same address, taxes for 2019, jointly bank account, joint credit card, phone bills, bank statements, life insurance, home insurance, pay stubs showing same address. I also added letters of support from friends. They didn't ask us for recent pictures and I wrote letter of explanation explaining we don't own car because they asked us for vehicle insurance on our names. After I sent them everything through email, we received Eligibility passed letter on account. We are common law.